I love their article on Nolan Ryan...
Our best estimate is that Nolan Ryan's pitch in 1974 was 108.1 mph FFE using today's standard of measurement at 50 feet from the plate.
Nolan Ryan was recorded by some Rockwell International scientists (likely by a coherent laser radar) at 100.9 mph, at 9-10 feet from plate (h), on 8/20/1974 in Anaheim Stadium (Angels) and the speed was verified by the Guinness Book of World Records (a). This record stands to this day.
The news of the new record created such a sensation that the Angels decided to have a promotion where fans would get to guess Ryan's fastest speed at the next home game. Ryan's pitch in that game reached 100.8 mph (at 9-10 feet from plate) on 9/7/1974 (a). See chart.
Today's pitch speeds are measured from 50 feet away from the plate, but Ryan's was measured at 10 feet. Pitch speeds drop 8-11 mph (average 9 mph) from 50 ft away to the front of the plate. So we must add 6-8 mph to the speed measured by Rockwell in order to be equivalent to today's readings.
Therefore, Nolan Ryan's pitching speed as measured today would be at minimum 106 mph and could have been as high as 110 mph.
How did we arrive at 108.1 mph? The facts are 100.9 at 10 feet, plus 9 mph drop per 50 feet. So add 7.2 mph (9/50*40) to 100.9 to get 108.1 mph.
There is a comparison of Nolan Ryan vs Joel Zumaya, complete with graph...